The present invention relates in general to the splitting of light beams and in particular to a new and useful device and method for splitting light beams through the use of a thin foil.
In the optics field, it is common to use a beam splitter which is made up of a glass or quartz, for splitting or dividing light beams. Usually, the known i.e. glass or quartz, beam splitter is mounted at some angle to the path of the light beam. A top surface of the beam splitter is then coated with a fragile coating. It is the optical properties of the coating which allows a portion of the light to be transmitted through the beam splitter while reflecting a uniform portion of the light from the top surface.
In these known devices, the beam splitting is controlled by controlling the coating on the top surface of the beam splitter. Thus, a reflection to transmission ratio, such as 50/50 or 70/30, can be achieved by varying the coating.
However, the known beam splitters do not split light wavelengths in the ultraviolet region in the same proportion as they split light wavelengths in the infrared region. When a known beam splitter is used, for example, in a detector for detecting flame in a boiler, this disparate splitting of the light wavelengths of the flame may cause a problem as the flame detector must detect a broad range of light wavelengths.
Because of the composition of these known beam splitters, i.e. quartz or glass, the production, manufacture and sale of the beam splitter prove to be very costly. In particular, the application of the coatings and the finishing of the surface to produce an efficient interface are both time consuming. In addition, the coatings used for these known beam splitters is also very expensive and fragile.
Additionally, another problem associated with known beam splitters is that some of the light is absorbed by the materials, thus reducing the total light transmitted through the beam splitter.